CRYPTOGRAPHY, STEGANOGRAPHY AND NETWORK SECURITIES

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Available Online At www.ijpret.com

INTERNATIONAL JOURNAL OF PURE AND

APPLIED RESEARCH IN ENGINEERING AND

TECHNOLOGY

A PATH FOR HORIZING YOUR INNOVATIVE WORK

CRYPTOGRAPHY, STEGANOGRAPHY &NETWORK SECURITIES

SHITAL C. PATIL1, PROF. R. R. KEOLE2

1. PG Students H.V.P.M’s college of Engg. & Tech., Amravati, India. 2. Faculty in H.V.P.M’s college of Engg. & Tech., Amravati, India.

Accepted Date:

27/02/2013 Publish Date:

01/04/2013

Keywords

Cryptography,

Steganography,

Authentication,

Security Techniques

Corresponding Author Ms. Shital C. Patil

Abstract

This paper presents a classification of network security techniques such as:

secrecy, authentication and Non-repudiation. The secrecy techniques are of

two categories: cryptography and steganography. Cryptographyis, traditionally,

the study of means of converting information from its normal, comprehensible

form into an incomprehensible format, rendering it unreadable without secret

knowledge, the art of encryption. Steganography is the art and science of

writing hidden messages in such a way that no one, apart from the sender and

intended recipient, suspects the existence of the message, a form of security

through obscurity. Steganography is often confused with cryptography

because the two are similar in the way that they both are used to protect

confidential information. The difference between the two is in the appearance

in the processed output; the output of steganography operation is not

apparently visible but in cryptography the output is scrambled so that it can

draw attention. Authentication is the act of confirming the truth of an attribute

of a datum or entity.If both cryptography and steganography are used then the

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Available Online At www.ijpret.com 1. INTRODUCTION

During the last few decades there is a

tremendous development in information

and communication technology. So security

in communication through internet has

become a concern. Network security

problems can be categorized roughly into

four areas: secrecy, authentication,

non-repudiation and integrity control. Secrecy,

also called confidentiality concerns with

keeping the information away from the

unauthorized users. That means

unauthorized users should not be able to

read and/or understand the information on

transit.

There are mainly two techniques to achieve

secrecy. Those are: cryptography and

steganography. Cryptography is a technique

in which the secret information is

transformed to a new form such that the

intruder can not understand information.

The Cryptographic algorithms are again two

types. They are: symmetric key

cryptography and public key cryptography.

Steganography is a technique of converting

communication in which the intruder can

not suspect that communication is going on

[1].The main goal of steganography is to

communicate securely in a completely

undetectable manner and to avoid drawing

suspicion to the transmission of a hidden a

data. It is not to keep others from knowing

hidden information even exist. If a

steganography method causes someone to

suspect the carrier medium then the

method has failed [2].

Authentication is the act of confirming the

truth of an attribute of a datum or entity.

This might involve confirming the identity of

a person or software program, tracing the

origins of an artifact, or ensuring that a

product is what its packing and labeling

claims to be.

Non-repudiation refers to a state of affairs

where the purported maker of a statement

will not be able to successfully challenge

the validity of the statement or contract [1].

2. CRYPTOGRAPHY

Cryptography is the art of protecting

information by encrypting it into an

unreadable format, called cipher text. Only

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decipher(or decrypt) the message into plain

text.

2.1. Symmetric Key Cryptography

This is the traditional cryptography known

as private key cryptography too. The sender

uses a key and the encryption procedure to

encrypt the message (plain text) into cipher

text. The receiver uses the decryption

procedure and the key to decrypt the cipher

text to message. The key at sender is same

as the key at the receiver. The encryption

and decryption procedures except the key

are known to the adversary, so the

protection of the data or message depends

on the key only. Fig.1 is a diagrammatical

representation of Symmetric Key

Cryptography . There are a good number of

symmetric key algorithms. Some well

known algorithms are: DES (Data Encryption

Standard), IDEA (International Data

Encryption Algorithm), Triple-DES, AES

(Advanced Encryption Standard), RC6 [1].

Figure 1: Symmetric Key Cryptography

2.2. Public Key Cryptography

In 1976 Diffie and Hellman developed a two

key crypto system, called public key

cryptography. The distinguishing technique

used in public-key cryptography is the use

of asymmetric key algorithms, where

the key used to encrypt a message is not

the same as the key used to decrypt it. Each

user has a pair of cryptographic keys –

a public encryption key and a private

decryption key. The publicly available

encrypting-key is widely distributed, while

the private decrypting-key is known only to

its proprietor, the recipient. Messages are

encrypted with the recipient's public key,

and can be decrypted only with the

corresponding private key. Some well

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(Rivest, Shamir and Adelman),

Diffie-Hellman etc [1].

3. STEGANOGRAPHY

Steganography is a technique for invisible

communication. This is achieved by hiding

information inside another information,

thus hiding the existence of the

communicated information.The word

steganography is ofGreek origin and means

"concealed writing" from the Greek words

steganos means "covered or protected",

and grapheimeans "writing".The advantage

of steganography over cryptography alone

is that messages do not attract attention to

themselves.

Modern techniques of steganography

Steganographic techniques are based on

the four types of cover files i.e. text, image,

audio and video files.

3.1 Text Steganography: [3]

In this technique the message is hidden

within a plain text file using

differentschemes like use of selected

characters, extra white spaces of the cover

text etc.

•Use of selected characters of cover Text.

Sender sends a series of integer number

(Key) to the recipient with a prioragreement

that the secret message is hidden within the

respective position ofsubsequent words of

the cover text. For example the series is ‘1,

1, 2, 3, 4, 2, 4,’and the cover text is “Ateam

of five men joined today”. So the

hiddenmessage is “Atfvoa”. A “0” in the

number series will indicate a blank space

inthe recovered message. The word in the

received cover text will be skipped if

thenumber of characters in that word is less

than the respective number in theseries

(Key) which shall also be skipped during the

process of message unhide.

•Use of extra white space characters of

cover text.

A number of extra blank spaces are inserted

between consecutive words of covertext.

This numbers are mapped to a hidden

message through an index of alookup table.

3.2 Image Steganography:

The most widely used technique today is

hiding of secret messages into a

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exploits the weakness of the human

visualsystem (HVS). HVS cannot detect the

variation in luminance of color vectors

athigher frequency side of the visual

spectrum. A picture can be represented by

a

collection of color pixels. The individual

pixels can be represented by their

opticalcharacteristics like 'brightness',

'chroma' etc. Each of these characteristics

can bedigitally expressed in terms of 1s and

0s.For example: a 24-bit bitmap will have 8

bits, representing each of the threecolor

values (red, green, and blue) at each pixel

[4].If we consider just the bluethere will be

28different values of blue. The difference

between 11111111 and11111110 in the

value for blue intensity is likely to be

undetectable by thehuman eye. Hence, if

the terminal recipient of the data is nothing

but humanvisual system (HVS) then the

Least Significant Bit (LSB) can be used

forsomething else other than color

information.

3.3 Audio Steganography[5,6,7]

In audio steganography, secret message is

embedded into digitized audio signalwhich

result slight altering of binary sequence of

the corresponding audio file.There are

several methods are available for audio

steganography. Some of themare LSB

Coding, Phase Coding, Spread

Spectrum,Echo Hiding etc.

Fig 2 : Audio Steganography

Audio File (host) Message

Alteration

Modification

Verification

Original sample New Sample

Reconstruction

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Available Online At www.ijpret.com 3.4 Video Steganography

Video files generally consist of images and

sounds, so most of the relevant techniques

for hiding data intoimages and audio are

also applicable to video media. In the case

of video steganography sender sends the

secretmessage to the recipient using a

video sequence as cover media. Optional

secret key ‘K’ can also be used

duringembedding the secret message to the

cover media to produce ‘stego-video’. After

that the stego-video iscommunicated over

public channel to the receiver. At the

receiving end, receiver uses the secret key

along with extraction algorithm to extract

the secret.

4. APPLICATIONS

4.1. Applications of Cryptography:

Cryptography is used for securing

transmission of messages, protection of

data, and to provide privacy and security in

any situation where information is not

intended for public consumption. Examples

include political campaign plans,

extramarital affairs, cover-ups, ecommerce,

business transactions, and private

communications.

4.2. Applications of steganography:

Usage in modern printers: Steganography is

used by some modern printers, including HP

and XEROX brand color laser printers. Tiny

yellow dots are added to each page. The

dots are barely visible and contain encoded

printer serial numbers, as well as date and

time stamps.

Alleged use by intelligence services: In

2010, the Federal Bureau

ofInvestigation revealed that the Russian

foreign intelligence service uses customized

steganography software for embedding

encrypted text messages inside image files

for certain communications with "illegal

agents" (agents under non-diplomatic

cover) stationed abroad.

To Control Terrorist Activities: How to

control terrorist activities is a big question

before many countries. The government

and anti-terrorism offices can communicate

secretly to monitor or stop the terrorist

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terrorists can be careful and change their

plans.

5. CONCLUSION

This paper presents a classification of

network security techniques and the recent

research work in the field of steganography.

Cryptography like Steganography is a very

useful technique to achieve secrecy in

communication. In areas where

cryptography and strong encryption are

being outlawed, citizens are looking at

steganography to circumvent such policies

andpass messages covertly.

REFERENCES

1. Gandharba Swain, Saroj Kumar Lanka, “A

Quick review of Network Security and

Steganography”, International Journal of

Electronics and Computer Science

Engineering, (IJECS- 2012),2012

2. M.I.Khalil, “Image Steganography: hiding

Short Audio Message within Digital Images”

,( JCS&T, 2011), 2011.

3. Soumyendu Das, Subhendu Das, Bijoy

Bandyopadhyay, Sugata Sanyal, “

Steganography and Stegnalysis: Different

Approaches”,

http://arxiv.org/ftp/arxiv/papers/111/358.p

df

4. Babloo Shaha and Suchi Sharma, “

Steganographic Techniques of Data Hiding

using Digital Images” , Defence Science

Journal, vol 62, No.1, 2012.

5. Bhavsar Jaimin H, Imaran Khan, “

Techniques of Steganography And

Steganalysis”,

http://ssrn.com/abstract=2029407.

6. Udit Budhiaa andDeepa Kundur, “Digital

video steganalysis exploiting collusion

sensitivity” - Sensors, Command Control,

Communications and Intelligence (C3I)

Technologies for Homeland Security and

Homeland Defense, Edward M.Carapezza,

ed., Proc. SPIE (vol. 5403), Orlando, Florida,

April 2004.

http://www.ece.tamu.edu/~deepa/pdf/Bud

Kun04.pdf

7. Methods of Audio Steganography,